Ventilation mask with integrated piloted exhalation valve and method of ventilating a patient using the same

ABSTRACT

In accordance with the present invention, there is provided a mask for achieving positive pressure mechanical ventilation (inclusive of CPAP, ventilator support, critical care ventilation, emergency applications), and a method for a operating a ventilation system including such mask. The mask of the present invention includes a piloted exhalation valve that is used to achieve the target pressures/flows to the patient. The pilot for the valve may be pneumatic and driven from the gas supply tubing from the ventilator. The pilot may also be a preset pressure derived in the mask, a separate pneumatic line from the ventilator, or an electro-mechanical control. Additionally, the valve can be implemented with a diaphragm or with a flapper.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication Ser. No. 61/499,950 entitled VENTILATION MASK WITHINTEGRATED PILOTED EXHALATION VALVE filed Jun. 22, 2011, and U.S.Provisional Patent Application Ser. No. 61/512,750 entitled VENTILATIONMASK WITH INTEGRATED PILOTED EXHALATION VALVE AND METHOD OF VENTILATINGA PATIENT USING THE SAME filed Jul. 28, 2011

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to systems and methods for controllingdelivery of a pressurized flow of breathable gas to a patient and, moreparticularly, to a ventilation mask such as a nasal mask, nasal prongsmask or nasal pillows mask for use in critical care ventilation,respiratory insufficiency or PAP (Positive Airway Pressure) therapy andincorporating a piloted exhalation valve inside the mask.

2. Description of the Related Art

As is known in the medical arts, mechanical ventilators comprise medicaldevices that either perform or supplement breathing for patients. Earlyventilators, such as the “iron lung”, created negative pressure aroundthe patient's chest to cause a flow of ambient air through the patient'snose and/or mouth into their lungs. However, the vast majority ofcontemporary ventilators instead use positive pressure to deliver gas tothe patient's lungs via a patient circuit between the ventilator and thepatient. The patient circuit typically consists of one or two large boretubes (e.g., 22 mm ID for adults; 15 mm ID for pediatric) that interfaceto the ventilator on one end and a patient mask on the other end. Mostoften, the patient mask is not provided as part of the ventilatorsystem, and a wide variety of patient masks can be used with anyventilator. The interfaces between the ventilator, patient circuit andpatient masks are standardized as generic 15 mm/22 mm conicalconnectors, the size and shape of which are specified by regulatorybodies to assure interoperability.

Current ventilators are designed to support either single limb or duallimb patient circuits. Ventilators using single limb patient circuit aremost typically used for less acute clinical requirements, such astreatment of obstructive sleep apnea or respiratory insufficiency.Ventilators using dual limb patient circuits are most typically used forcritical care applications.

Single limb patient circuits are used only to carry gas flow from theventilator to the patient and patient mask, and require a patient maskwith vent holes. The pressure/flow characteristics of the vent holes inthe mask are maintained according to standards that assureinteroperability of masks with a multitude of ventilators that followthe standard. When utilizing single limb circuits, the patient inspiresfresh gas from the patient circuit, and expires CO2-enriched gas, whichis purged from the system through the vent holes in the mask andpartially breathed down the tube to the ventilator and re-breathedduring the next breath. This constant purging of flow through vent holesin the mask when using single-limb circuits provides severaldisadvantages: 1) it requires the ventilator to provide significantlymore flow than the patient requires, adding cost/complexity to theventilator and requiring larger tubing; 2) the constant flow through thevent holes creates noise, which has proven to be a significant detrimentto patients with sleep apnea that are trying to sleep with the mask, andalso to their sleep partners; 3) the additional flow coming intoproximity of the patient's nose and then exiting the system often causesdryness in the patient, which often drives the need for addinghumidification to the system; and 4) patient-expired CO2 flows partiallyout of the vent holes in the mask and partially into the patient circuittubing, requiring a minimum flow through the tubing at all times inorder to flush the CO2. To address the problem of undesirable flow ofpatient-expired CO2 back into the patient circuit tubing, currentlyknown CPAP systems typically have a minimum-required pressure of 4 cmH2Owhenever the patient is wearing the mask, which produces significantdiscomfort, claustrophobia and/or feeling of suffocation to early CPAPusers and leads to a high (approximately 50%) non-compliance rate withCPAP therapy.

When utilizing dual limb circuits, the patient inspires fresh gas fromone limb (the “inspiratory limb”) of the patient circuit and expiresCO2-enriched gas from the second limb (the “expiratory limb”) of thepatient circuit. Both limbs of the dual limb patient circuit areconnected together in a “Y” proximal to the patient to allow a single 15mm or 22 mm conical connection to the patient mask.

In the patient circuits described above, the ventilator pressurizes thegas to be delivered to the patient inside the ventilator to the intendedpatient pressure, and then delivers that pressure to the patient throughthe patient circuit. Very small pressure drops develop through thepatient circuit, typically around 1 cmH2O, due to gas flow though thesmall amount of resistance created by the 22 mm or 15 mm ID tubing. Someventilators compensate for this small pressure either by mathematicalalgorithms, or by sensing the tubing pressure more proximal to thepatient.

Ventilators that utilize a dual limb patient circuit typically includean exhalation valve at the end of the expiratory limb proximal to theventilator. The ventilator controls the exhalation valve, closes itduring inspiration, and opens it during exhalation. Less sophisticatedventilators have binary control of the exhalation valve, in that theycan control it to be either open or closed. More sophisticatedventilators are able to control the exhalation valve in an analogfashion, allowing them to control the pressure within the patientcircuit by incrementally opening or closing the valve. Valves thatsupport this incremental control are referred to as active exhalationvalves. In existing ventilation systems, active exhalation valves aremost typically implemented physically within the ventilator, and theremaining few ventilation systems with active exhalation valves locatethe active exhalation valve within the patient circuit proximal to theventilator. Active exhalation valves inside ventilators are typicallyactuated via an electromagnetic coil in the valve, whereas activeexhalation valves in the patient circuit are typically pneumaticallypiloted from the ventilator.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a mask forachieving positive pressure mechanical ventilation (inclusive of PAP,ventilatory support, critical care ventilation, emergency applications),and a method for a operating a ventilation system including such mask.The mask may include a pressure sensing modality proximal to the patientconnection. Such pressure sensing modality may be a pneumatic port withtubing that allows transmission of the patient pressure back to theventilator for measurement, or may include a transducer within the mask.The pressure sensing port, if included in the mask, is used in thesystem to allow pressure sensing for achieving and/or monitoring thetherapeutic pressures. Alternately or additionally, the mask may includea flow sensing modality located therewithin for achieving and/ormonitoring the patient and/or therapeutic flows.

The mask of the present invention also includes a piloted exhalationvalve that is used to achieve the target pressures/flows to the patient.In the preferred embodiment, the pilot for the valve is pneumatic anddriven from the gas supply tubing from the ventilator. The pilot canalso be a preset pressure derived in the mask, a separate pneumatic linefrom the ventilator, or an electro-mechanical control. In accordancewith the present invention, the valve can be implemented with adiaphragm or with a flapper.

One of the primary benefits attendant to including the valve inside themask is that it provides a path for patient-expired CO2 to exit thesystem without the need for a dual-limb patient circuit, and without thedisadvantages associated with traditional single-limb patient circuits.For instance, in applications treating patients with sleep apnea, havingthe valve inside the mask allows patients to fall asleep while wearingthe mask without the treatment pressure turned on, thereby preventingpatient discomfort typically experienced with falling asleep whilebreathing at a positive pressure. In accordance with the presentinvention, the sensing described above may be used to sense apredetermined event, such as a set time, the detection of an eventindicating patient airway obstruction, or the detection of a patientfalling asleep, and start the positive airway pressure therapy uponsensing any such event, unlike existing devices which attempt toalleviate patient discomfort by starting at a lower pressure level(typically 4 cmH2O) and ramping the pressure up to a therapeutic levelover a period of time. Additionally, having a valve inside the maskmitigates the need to have vent holes within the patient mask (a typicalfeature of mask used for sleep apnea) coincident with a purge flow tobleed patient expired CO2 from the system. Alleviating the mask ventholes and associated extra flow of gas through the mask helps reducenoise generated by the mask, reduce CO2 re-breathing, reduce patientnose dryness cause by excess gas flowing past the patient, and reduceflow requirements of the ventilator. Yet another benefit of the maskwithout vent holes and having the valve inside the same is that becausethere is not a constant flow through the mask and out of any vent holes,a heat moisture exchanger can also be incorporated into the mask,allowing a simple method of providing heated and humidified gas to thepatient.

Another benefit for having the valve inside the mask is that it allowsfor a significant reduction in the tubing size, as it supports theventilator delivering higher pressures than the patient's therapeuticpressure. In this regard, pressure from the ventilator is significantlyhigher than the patient's therapeutic pressure. Pressure sensing can beimplemented inside the mask near the patient interface port(s),facilitating the ventilator to have a means to servo control pressure atthe patient interface port(s). Having higher pressure from theventilator and an active exhalation valve in the mask allows for thetubing size to be significantly smaller (e.g. 1-9 mm ID) compared toconventional ventilators (22 mm ID for adults/15 mm ID for pediatric).One obvious benefit of smaller tubing is that it provides less bulk forpatient and/or caregivers to manage. For today's smallest ventilators,the bulk of the tubing is as significant as the bulk of the ventilator.Another benefit of the smaller tubing is that is allows for moreconvenient ways of affixing the mask to the patient. For instance, thetubing can go around the patient's ears to hold the mask to the face,instead of requiring straps (typically called “headgear”) to affix themask to the face. Along these lines, the discomfort, complication, andnon-discrete look of the headgear is another significant factor leadingto the high non-compliance rate for CPAP therapy. Another benefit to thesmaller tubing is that the mask can become smaller because it does notneed to interface with the large tubing. Indeed, large masks are anothersignificant factor leading to the high non-compliance rate for CPAPtherapy since, in addition to being non-discrete, they often causeclaustrophobia.

The present invention is best understood by reference to the followingdetailed description when read in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These, as well as other features of the present invention, will becomemore apparent upon reference to the drawings wherein:

FIG. 1 is an isometric view of a nasal pillows mask constructed inaccordance with a first embodiment of the present invention andincluding an integrated diaphragm-implementation piloted exhalationvalve;

FIG. 2 is a front elevational view of the nasal pillows mask shown inFIG. 1;

FIG. 3 is a cross-sectional view of the nasal pillows mask shown in FIG.2;

FIG. 4 is an exploded, cross-sectional front view of the nasal pillowsmask shown in FIG. 3;

FIG. 5 is a front elevational view of a nasal pillows mask constructedin accordance with a second embodiment of the present invention andincluding an integrated flapper-implementation exhalation valve;

FIG. 6 is a top plan view of the nasal pillows mask shown in FIG. 5;

FIG. 7 is a bottom plan view of the nasal pillows mask shown in FIG. 5;

FIG. 8 is a cross-sectional, isometric view of the nasal pillows maskshown in FIG. 5; and

FIG. 9 is a cross-sectional view of the nasal pillows mask shown in FIG.5.

Common reference numerals are used throughout the drawings and detaileddescription to indicate like elements.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings wherein the showings are for purposes ofillustrating various embodiments of the present invention only, and notfor purposes of limiting the same, FIGS. 1-4 depict a ventilation mask10 constructed in accordance with a first embodiment of the presentinvention. The mask is depicted as a nasal prongs mask, however thoseskilled in the art will recognize that other ventilation masks arecontemplated herein such as nasal pillows masks, nasal masks andoronasal masks and for purposes of this application the term mask and/orventilation mask will include all such mask structures. Additionally,for purposes of this application, the term “direct nasal interface mask”will be deemed to encompass those masks which are configured tofacilitate the direct introduction of therapeutic fluid pressure intothe nostrils of a patent, such masks including, but not being limitedto, nasal pillows masks, nasal prongs masks, and nasal cradle masks. Themask 10 includes an integrated, diaphragm-implemented, pilotedexhalation valve 12, the structural and functional attributes of whichwill be described in more detail below.

As seen in FIGS. 1-4, the mask 10 comprises a housing 14 which definesfirst and second fluid flow passages 16, 18. As best seen in FIGS. 3 and4, the flow passages 16, 18 are formed within the housing 14 to havesubstantially identical shapes or contours. Although illustrated with apair of flow passages, 16, 18, those skilled in the art will recognizethat a single flow passage is additionally contemplated herein. In themask 10, one end of each of the flow passages 16, 18 is defined by arespective one of an identically configured pair of generallycylindrical, tubular protrusions 20 a, 20 b of the housing 14. Theopposite end of each of the flow passages 16, 18 is defined by arespective one of an identically configured pair of connector ports 22a, 22 b of the housing 14. As seen in FIGS. 3 and 4, the connector ports22 a, 22 b are each sized and configured to accommodate the advancementof a distal end portion of a tubular fluid line 24 therein. As isapparent from FIG. 3, the operative engagement of a fluid line 24 toeach of the connector ports 22 a, 22 b effectively places such fluidlines 24 into fluid communication with respective ones of the flowpassages 16, 18. In the housing 14, the spacing between the protrusions20 a, 20 b is selected to facilitate the general alignment thereof withthe nostrils of an adult patient when the mask 10 is worn by suchpatient.

In the mask 10, the flow passages 16, 18 are preferably not fluidlyisolated from each other. Rather, as also seen in FIGS. 3 and 4, thehousing 14 may define an optional cross passage 26 which extends betweenthe protrusions 20 a, 20 b thereof, and effectively places the flowpassages 16, 18 into fluid communication with each other. The crosspassage 26 is further placed into fluid communication with ambient airby an optional vent port 28 which is fluidly coupled thereto. The ventport 28 is defined by and extends axially through a generallycylindrical boss 30 of the housing 14 which protrudes upwardly betweenthe protrusions 20 a, 20 b thereof.

The housing 14 of the mask 10 further defines an internal valve chamber32 which fluidly communicates with the cross passage 26. As further seenin FIGS. 3 and 4, disposed at the junction between the cross passage 26and valve chamber 32 is a tubular projection 34 of the housing 14. Theprojection 34 defines an annular distal rim or seating surface 36 whichis used in the operation of the valve 12 in manner which will bedescribed in more detail below. The projection 34 protrudes into thevalve chamber 32, and defines the conduit which places the valve chamber32 into fluid communication with the cross passage 26.

As best seen in FIGS. 3 and 4, the valve chamber 32 is defined in largemeasure by a valve wall 38 of the housing 14 which is generally orientedbetween the flow passages 16, 18 thereof and, when viewed from theperspective shown in FIGS. 1-4, is disposed below the cross passage 26.As is also apparent from FIGS. 1 and 2, the valve wall 38 has aperforated construction, thus facilitating the fluid communicationbetween the valve chamber 32 partially defined thereby and ambient air.

In the mask 10, the end of the valve chamber 32 disposed furthest fromthe cross passage 26 is enclosed by a valve cap 40 which may beremovably attached or permanently attached to the distal portion or rimof the valve wall 38 in the manner best seen in FIG. 3. The valve cap 40includes a pilot port 42 which, when the valve cap 40 is coupled to thevalve wall 38, is placed into fluid communication with the valve chamber32. The pilot port 42 is partially defined by and extends axiallythrough a generally cylindrical connector 44 of the valve cap 40. Asbest seen in FIGS. 3 and 4, one end of the pilot port 42 is disposedwithin a generally planar base surface 46 defined by the valve cap 40.In addition to the base surface 46, the valve cap 40 defines acontinuous shoulder 48 which, from the perspective shown in FIG. 4, iselevated above the base surface 46. This embodiment shows apneumatically piloted diaphragm; it is additionally contemplated thatthe valve 12 can be driven in an electromechanical manner (e.g., with anelectromagnet instead of using the above mentioned pilot port 42).

The mask 10 of the present invention further comprises a diaphragm 50which resides within the valve chamber 32. Although variousconfigurations of diaphragms 50 are contemplated herein, as is also bestseen in FIGS. 3 and 4, the diaphragm 50 has an enlarged, central mainbody portion 52, and a peripheral flange portion 54 which is integrallyconnected to and circumvents the main body portion 52. The flangeportion 54 includes an arcuately contoured central region which isoriented between the distal region thereof and the main body portion 52,and defines a continuous, generally concave channel 56. The diaphragm 50is preferably fabricated from a suitable resilient material.

In the mask 10, the distal region of the flange portion 54 of thediaphragm 50 which is disposed outward of the arcuate central regionthereof is normally captured between the valve cap 40 and the valve wall38 when the valve cap 40 is operatively engaged to the valve wall 38.More particularly, as seen in FIG. 3, the distal region of the flangeportion 54 is compressed and thus captured between the shoulder 48 ofthe valve cap 40 and a lip portion 58 of the valve wall 38 whichprotrudes inwardly from the inner surface thereof. The diaphragm 50 ispreferably sized such that when the distal region of the flange portion54 thereof is captured between the shoulder 48 and lip portion 58 in theaforementioned manner, the arcuate central region of the flange portion54 is disposed directly adjacent the inner peripheral surface of the lipportion 58. Additionally, the channel 56 defined by the flange portion54 is directed toward and thus faces the base surface 46 of the valvecap 40.

In the mask 10, the diaphragm 50 effectively segregates the valvechamber 32 into a patient side or region 32 a, and a pilot side orregion 32 b. More particularly, due to the aforementioned manner inwhich the diaphragm 50 is captured between the valve cap 40 and thevalve wall 38, the patient and pilot regions 32 a, 32 b of the valvechamber 32 are separated from each other by the diaphragm 50, and are ofdiffering volumes. Along these lines, the fluid conduit defined by theprojection 34 communicates directly with the patient region 32 a of thevalve chamber 32, while the pilot port 42 defined by the connector 44communicates directly with the pilot region 32 b of the valve chamber32.

The diaphragm 50 (and hence the valve 12) is selectively moveablebetween an open position (shown in FIG. 3) and a closed position.Importantly, in either of its open or closed positions, the diaphragm 50is not seated directly against the base surface 46 of the valve cap 40.Rather, a gap is normally maintained therebetween. As seen in FIG. 3,the width of such gap when the diaphragm 50 is in its open position isgenerally equal to the fixed distance separating the base surface 46 ofthe valve cap 40 from the shoulder 48 thereof. When the diaphragm 50 isin its open position, it is also disposed in spaced relation to theprojection 34 of the housing 14, and in particular the seating surface36 defined thereby. As such, when the diaphragm 50 is in its openposition, fluid is able to freely pass between the flow passages 16, 18and ambient air via the cross passage 26, the flow conduit defined bythe projection 34, and the perforated openings within the valve wall 38partially defining the valve chamber 32.

The diaphragm 50 may be resiliently deformable from its open position(to which it may be normally biased) to its closed position. It is animportant feature of the present invention that the diaphragm 50 isnormally biased in its open position which provides a fail safe to allowa patient to inhale ambient air through the valve and exhale ambient airthrough the valve even during any ventilator malfunction.

When moved or actuated to the closed position, the main body portion 52of the diaphragm 50 is firmly seated against the seating surface 36defined by the projection 34, thus effectively blocking fluidcommunication between the cross passage 26 (and hence the flow passages16, 18) and the valve chamber 32. More particularly, when viewed fromthe perspective shown in FIG. 3, the peripheral region of the topsurface of the main body portion 52 is seated against the seatingsurface 36, with a central region of the top surface of the main bodyportion 52 protruding slightly into the interior of the projection 34,i.e., the fluid conduit defined by the projection 34.

As is apparent from the foregoing description, in the mask 10, the valve12 thereof is collectively defined by the projection 34, valve wall 38,valve cap 40 and diaphragm 50. Additionally, in the mask 10, it iscontemplated that the valve 12 will be piloted, with the movement of thediaphragm 50 to the closed position as described above being facilitatedby the introduction of positive fluid pressure into the gap normallydefined between the diaphragm 50 and the base surface 46 via the pilotport 42, i.e., into the pilot region 32 b of the valve chamber 32. Inthis regard, it is contemplated that during the use of the mask 10 by apatient, a pilot fluid line (not shown) from a ventilator will becoupled to the connector 44. It is also contemplated that during theinspiratory phase of the breathing cycle of the patient wearing the mask10, the fluid pressure level introduced into the pilot region 32 b ofthe valve chamber 32 via the pilot port 42 will be sufficient tofacilitate the movement of the diaphragm 50 to its closed position.Conversely, during the expiratory phase of the breathing cycle of thepatient wearing the mask 10, it is contemplated that the discontinuationof the fluid flow through the pilot port 42, coupled with the resiliencyof the diaphragm 50, a biasing spring (not shown) operatively coupled tothe main body portion 52 of the diaphragm 50, and/or positive pressureapplied to the main body portion 52 of the diaphragm 50, will facilitatethe movement of the diaphragm 50 back to the open position. As will berecognized, the movement of the diaphragm 50 to the open position allowsthe air exhaled from the patient to be vented to ambient air afterentering the patient region 32 a of the valve chamber 32 via theperforated openings of the valve wall 38 communicating with the valvechamber 32.

As will be recognized, based upon the application of pilot pressure, thediaphragm 50 travels from a fully open position through a partially openposition to a fully closed position. In this regard, the diaphragm 50will be partially open or partially closed during exhalation to maintaindesired ventilation therapy. Additionally, a positive airway pressurecan be controlled with any expiratory flow value by modulating the pilotpressure within the pilot region 32 b of the valve chamber 32 and hencethe position of the diaphragm 50. Further, when pilot pressure isdiscontinued to the diaphragm, the diaphragm 50 moves to an openposition wherein the patient can inhale and exhale through the mask withminimal restriction and with minimal carbon dioxide retention within themask 10. This is an important feature of the present invention whichallows a patient to wear the mask 10 without ventilation therapy beingapplied to the mask such that the mask 10 is comfortable to wear and canbe worn without carbon dioxide buildup. This feature is highlyadvantageous for the treatment of obstructive sleep apnea where patientscomplain of discomfort with ventilation therapy due to mask and pressurediscomfort. When it is detected that a patient requires sleep apneatherapy, the ventilation therapy can be started (i.e., in an obstructivesleep apnea situation).

In this regard, the present invention contemplates a method ofventilation utilizing a mask wherein patient inhalation and patientexhalation is facilitated through the mask to ambient air when theventilator is not delivering a therapeutic level of pressure. Forinstance, additional valving in the mask may be implemented for thispurpose. Since the mask does not facilitate CO2 buildup, the ventilatorcan remain off while the mask is worn by the patient and ventilationtherapy can be initiated upon sensing or detecting a patientrequirement, such as sleep apnea therapy, by conventional sensorsincorporated into the mask and ventilator. In this regard, conventionalventilators can be readily modified via conventional software changes toallow the mask to be worn without supplying pressure to the mask unlessand until a patient requirement is sensed and subsequently communicatedto the ventilator to provide necessary ventilation to the patient. Suchmodification may additionally require the use of a conventional checkvalve to ensure that patient exhalation is facilitated through theexhalation valve on the mask and not back into the ventilator deliverycircuit.

As indicated above, in the embodiment shown in FIGS. 1-4, the diaphragm50 is pneumatically piloted, with the position thereof being regulatedby selectively modulating the pilot pressure within the pilot region 32b of the valve chamber 32. However, it is contemplated that alternativemodalities, such as an electromagnetic actuator, can be used to drivethe valve 12. For example, as also indicated above, in an alternativeembodiment, the valve 12 may be driven in an electromechanical mannerthrough the use of an electromagnet instead of using the above-describedpilot port 42.

As indicated above, in the mask 10, the valve cap 40 is releasablyattached to the valve wall 38 of the housing 14. As a result, theselective detachment of the valve cap 40 from the housing 14 allows forthe removal of the diaphragm 50 from within the valve chamber 32 aspermits the periodic cleaning or disinfection thereof. In addition, thedetachment of the valve cap 40 from the valve wall 38 of the housing 14also permits access to and the cleaning or disinfection of the interiorsurfaces of the valve chamber 32. Port 28 provides a means for pressuremeasurement inside the mask.

Referring now to FIGS. 5-9, there is shown a nasal pillows mask 100constructed in accordance with a second embodiment of the presentinvention. The mask 100 includes an integrated, flapper-implementedexhalation valve 112, the structural and functional attributes of whichwill be described in more detail below.

As seen in FIGS. 5-9, the mask 100 comprises a housing 114 which definesfirst and second fluid flow passages 116, 118. As seen in FIGS. 8 and 9,the flow passages 116, 118 are formed within the housing 114 to havesubstantially identical shapes or contours. As with the first embodimentof this invention, a single flow passage is additionally expresslycontemplated herein. In the mask 100, one end of each of the flowpassages 116, 118 is defined by a respective one of an identicallyconfigured pair of generally cylindrical, tubular protrusions 120 a, 120b of the housing 114. The opposite end of each of the flow passages 116,118 is defined by a respective one of an identically configured pair ofconnector ports 122 a, 122 b of the housing 114. The connector ports 122a, 122 b are each sized and configured to accommodate the advancementand frictional retention of a distal end portion of a tubular fluid line124 therein. As most apparent from FIGS. 8 and 9, the operativeengagement of a fluid line 124 to each of the connector portions 122 a,122 b effectively places such fluid lines 124 into fluid communicationwith respective ones of the flow passages 116, 118. In the housing 114,the spacing between the protrusions 120 a, 120 b is selected tofacilitate the general alignment thereof with the nostrils of an adultpatient when the mask 100 is worn by such patient.

In the mask 100, the flow passages 116, 118 are not fluidly isolatedfrom each other. Rather, as seen in FIGS. 8 and 9, the housing 114further defines an optional cross passage 126 which extends between theprotrusions 120 a, 120 b thereof, and effectively places the flowpassages 116, 118 into fluid communication with each other. The crosspassage 126 is further placed into communication with ambient air by anidentically configured pair of vent ports 128 which are fluidly coupledthereto. The vent ports 128, which are disposed in side-by-side, spacedrelation to each other, are formed within the housing 14 between theprotrusions 120 a, 120 b thereof and, when viewed from the perspectiveshown in FIG. 9, face downwardly in a direction opposite that of theopen distal ends of the protrusions 120 a, 120 b.

As is best seen in FIGS. 8 and 9, the protrusions 120 a, 120 b arepreferably formed as separate and distinct components or sections of thehousing 114 which, when mated to the remainder thereof, facilitate theformation of an identically configured pair of arcuate, semi-circularshoulders 130 a, 130 b. The shoulders 130 a, 130 b defined by thehousing 114 are located within the interiors of respective ones of theprotrusions 120 a, 120 b thereof. More particularly, each shoulder 130a, 130 b is formed in close proximity to that end of the correspondingprotrusion 120 a, 120 b disposed furthest from the open distal endthereof. The use of the shoulders 130 a, 130 b will be described in moredetail below.

In the mask 100, the cross passage 126 is partially defined by one ormore valve projections 132 a, 132 b of the housing 114 which areintegrally connected to respective ones of the protrusions 120 a, 120 b,and protrude generally perpendicularly from the inner surfaces thereofin opposed relation to each other. As seen in FIGS. 6, 8, and 9, thevalve projections 132 a, 132 b are not sized to completely span or coverthose portions of the flow passages 116, 118 defined by the protrusions120 a, 120 b. Rather, each of the valve projections 132 a, 132 b isformed to define an arcuate peripheral edge segment, and sized such thatthe arcuate peripheral edge segment thereof is separated or spaced fromthe inner surface of the corresponding protrusion 120 a, 120 b by a gapwhich is of a prescribed width. Further, as seen in FIGS. 6 and 8, eachof the valve projections 132 a, 132 b preferably includes a plurality offlow openings 134 disposed therein in a generally circular pattern. Theflow openings 134 of the valve projections 132 a, 132 b each fluidlycommunicate with the cross passage 126, and are used for purposed whichwill also be described in more detail below.

The mask 100 of the present invention further comprises a flapper, whichis preferably segregated into an identically configured pair of flappersegments 136 a, 136 b. The flapper segments 136 a, 136 b are eachpreferably fabricated from a suitable, resilient material. As seen inFIGS. 8 and 9, the flapper segments 136 a, 136 b reside within theinteriors of respective ones of the protrusions 120 a, 120 b.Additionally, when viewed from the perspective shown in FIGS. 8 and 9,an inner end portion of each of the flapper segments 136 a, 136 b isfirmly secured to the housing 114 as a result of being captured betweenprescribed components or sections thereof. However, those portions ofthe flapper segments 136 a, 136 b not rigidly secured to the housing 114are free to resiliently move relative thereto, in a manner which will bedescribed in more detail below.

The flapper segments 136 a, 136 b (and hence the valve 112) areselectively moveable between a closed position (shown in FIGS. 8 and 9)and an open position. When the flapper segments 136 a, 136 b are each inthe open position, that portion of the peripheral edge thereof notsecured to the housing 114 (i.e., not captured between separate sectionsof the housing 114) is normally seated against a corresponding one ofthe shoulders 130 a, 130 b. As a result, any fluid (e.g., air exhaledfrom the nose of a patient wearing the mask) flowing into the flowpassages 116, 118 via the open distal ends of the protrusions 120 a, 120b is vented to ambient air via the cross passage 126 and vent ports 128.In this regard, such fluid is able to enter the cross passage 126through the gaps defined between the valve projections 132 a, 132 b andinner surfaces of the corresponding protrusions 120 a, 120 b.

The flapper segments 136 a, 136 b may be resiliently deformable from theopen position described above (to which they are normally biased) to theclosed position shown in FIGS. 8 and 9. More particularly, when moved oractuated to the closed position, those portions of the flapper segments136 a, 136 b not secured to the housing 114 are effectively placed intosealed contact with peripheral portions of respective ones of the valveprojections 132 a, 132 b in a manner substantially covering orobstructing the opposed ends of the cross passage 126 fluidlycommunicating the flow passages 116, 118. However, even when the flappersegments 136 a, 136 b are in the closed position, some measure of fluidmay still be vented from the flow passages 116, 118 to ambient air byentering the cross passage 126 via the flow openings 134 included ineach of the valve projections 132 a, 132 b.

As is apparent from the foregoing description, in the mask 100, thevalve 112 thereof is collectively defined by the shoulders 130 a, 130 b,valve projections 132 a, 132 b, and flapper segments 136 a, 136 b of theflapper. Additionally, in the mask 100, it is contemplated that theflapper segments 136 a, 136 b will normally be biased to the openposition. In this regard, it is contemplated that during the inspiratoryphase of the breathing cycle of a patient using the mask 100, positivefluid pressure introduced into the flow passages 116, 118 by aventilator fluidly coupled thereto via the fluid lines 124 will actagainst the flapper segments 136 a, 136 b in a manner facilitating themovement of such flapper segments 136 a, 136 b from their normally openposition, to the closed position shown in FIGS. 8 and 9. As a result,fluid is able to flow freely through the flow passages 116, 118 into thepatient's nostrils, and is substantially prevented from being vented toambient air via the cross passage 126, except for a small portion offlow that passes through flow openings 134. This small flow through flowopenings 134 provides for a means to bleed off pressure and thereforemore easily control the valve.

Conversely, during the expiratory phase of the breathing cycle of thepatient wearing the mask 100, it is contemplated that a reduction in thefluid pressure level introduced into the flow passages 116, 118 from thefluid lines 124 to below a prescribed level will allow the flappersegments 136 a, 136 b to resiliently return to their normal, openpositions engaging respective ones of the shoulders 130 a, 130 b. Whenthe flapper segments 136 a, 136 b return to their open positions, airexhaled from the patient's nostrils during the expiratory phase of thepatient's breathing circuit is vented to ambient air via the crosspassage 126 and vent ports 128. In this regard, though the movement ofthe flapper segments 136 a, 136 b to the open positions effectivelyblocks those portions of the flow passages 116, 118, air exhaled fromthe patient is able to flow through the gaps defined between the valveprojections 132 a, 132 b and the inner surfaces of the protrusions 120a, 120 b, and hence into the opposed open ends of the cross passage 126.

Advantageously, the mask 100 constructed in accordance with the presentinvention has a total flow requirement which is much lower in comparisonto that of a traditional vented PAP mask. This provides the mask 100with several advantages, including: reduced flow from the ventilator,and thus the ability to use smaller tubes; a reduction in the conductednoise from the ventilator to ambient air through the open vent ports 128in the mask 100; a reduction in oxygen consumption when required withthe PAP therapy due to lower flow requirements; and a reduction in waterconsumption of a humidifier due to lower flow requirements.

This disclosure provides exemplary embodiments of the present invention.The scope of the present invention is not limited by these exemplaryembodiments. Numerous variations, whether explicitly provided for by thespecification or implied by the specification, such as variations instructure, dimension, type of material and manufacturing process may beimplemented by one of skill in the art in view of this disclosure.

1. A method of ventilating a patient utilizing a direct nasal interfacemask worn by the patient and fluidly connected to a ventilator adaptedto supply a pressurized, breathable gas to the direct nasal interfacemask, the method comprising the steps of: a) providing the direct nasalinterface mask with a housing defining at least one flow passage, and anexhalation valve which is integrated into the housing and fluidlycoupled to the flow passage; and b) selectively moving the exhalationvalve being between a closed position wherein fluid flow between theflow passage and ambient air is at least partially obstructed thereby,and an open position wherein at least a portion of the flow passage isvented to ambient air.
 2. The method of claim 1 wherein step (a)comprises configuring the exhalation valve to completely obstruct fluidflow between the flow passage and ambient air when moved to the closedposition in step (b).
 3. The method of claim 1 wherein step (a)comprises configuring the exhalation valve to vent the entirety of theflow passage to ambient air when moved to the open position in step (b).4. The method of claim 1 wherein step (a) comprises configuring theexhalation valve to adjust fluid flow between the flow passage andambient air when disposed between the closed position and open positionin step (b).
 5. The method of claim 1 wherein step (a) comprisesconfiguring the housing to include a pressure sensing port, and step (b)comprises sensing pressure within the flow passage through the use ofthe pressure sensing port to facilitate at least one of achieving andmonitoring a therapeutic pressure level therein.
 6. The method of claim1 wherein step (a) comprises configuring the exhalation valve to bepiloted, and step (b) comprises applying a pilot pressure to theexhalation valve via the ventilator in a manner facilitating themovement of the exhalation valve to the closed position.
 7. The methodof claim 6 wherein step (a) comprises configuring the exhalation valveto include a diaphragm which is movable between the closed and openpositions in step (b), and is normally biased to the open position. 8.The method of claim 1 wherein step (a) comprises configuring theexhalation valve to include at least one flapper which is movablebetween the closed and open positions in step (b), and is normallybiased to the open position.
 9. The method of claim 1 wherein step (a)comprises configuring the exhalation valve to be normally biased to theopen position described in step (b), which further comprises initiallysupplying no pressurized, breathable gas from the ventilator to thepatient via the direct nasal interface mask.
 10. The method of claim 9further comprising the step of: c) facilitating the movement of theexhalation valve to the closed position, and initiating the delivery ofthe pressurized, breathable gas from the ventilator to the patient at aprescribed therapeutic pressure level upon an occurrence of apredetermined event.
 11. The method of claim 10 wherein thepredetermined event of step (c) is at least one of: i) an elapse of aset time interval; ii) a detection of a patient breathing patternindicative of an airway obstruction in the patient; and iii) a detectionof a patient breathing pattern indicative of the patient falling asleep.12. A method of ventilating a patient using a direct nasal interfacemask worn by the patient and fluidly connected to a ventilator adaptedto supply a pressurized, breathable gas to the direct nasal interfacemask, the method comprising the steps of: a) providing the direct nasalinterface mask with a housing at least partially defining a valvechamber which fluidly communicates with ambient air, a pilot port whichfluidly communicates with the valve chamber, at least one flow passagewhich is selectively placeable into fluid communication with the valvechamber, and a diaphragm which is disposed within the valve chamber andselectively movable between a closed position wherein fluid flow betweenthe flow passage and the valve chamber is obstructed thereby, and anopen position wherein the flow passage is vented to ambient air via thevalve chamber; and b) using the pilot port to selectively apply a pilotpressure to the diaphragm in a manner facilitating the movement thereofbetween the open and closed position.
 13. The method of claim 12 whereinstep (a) comprises configuring the housing to include a pressure sensingport which fluidly communicates with the flow passage, and step (b)comprises sensing pressure within the flow passage through the use ofthe pressure sensing port to facilitate at least one of achieving andmonitoring a therapeutic pressure level therein.
 14. The method of claim12 wherein step (a) comprises configuring the direct nasal interfacemask such that the diaphragm is normally biased to the open position,and step (b) comprises applying the pilot pressure to the diaphragm viathe ventilator in a manner facilitating the movement of the diaphragm tothe closed position.
 15. The method of claim 14 wherein step (b) furthercomprises initially supplying no pressurized, breathable gas from theventilator to the patient via the direct nasal interface mask, andinitially supplying no pilot pressure from the ventilator to thediaphragm.
 16. The method of claim 15 further comprising the step of: c)initiating the delivery of the pilot pressure from the ventilator to thediaphragm to facilitate the movement of the diaphragm to the closedposition, and further initiating the delivery of the pressurized,breathable gas from the ventilator to the patient at a prescribedtherapeutic pressure level upon an occurrence of a predetermined event.17. The method of claim 16 wherein the predetermined event of step (c)is at least one of: i) an elapse of a set time interval; ii) a detectionof a patient breathing pattern indicative of an airway obstruction inthe patient; and iii) a detection of a patient breathing patternindicative of the patient falling asleep.
 18. The method of claim 15further comprising the steps of: c) initiating the delivery of the pilotpressure from the ventilator to the diaphragm to facilitate the movementof the diaphragm to the closed position and further initiating thedelivery of the pressurized, breathable gas from the ventilator to thedirect nasal interface mask through the use of tubing having an innerdiameter in the range of from about 1 mm to about 9 mm; and d)delivering the pressurized, breathable gas from the ventilator to thedirect nasal interface mask through the tubing at a delivery pressurelevel which exceeds a prescribed therapeutic pressure level for thedelivery of the pressurized, breathable gas from the direct nasalinterface mask to the patient.
 19. A method of ventilating a patientusing a direct nasal interface mask worn by the patient and fluidlyconnected to a ventilator adapted to supply a pressurized, breathablegas to the direct nasal interface mask, the method comprising the stepsof: a) maintaining the direct nasal interface mask on the patientwithout initially supplying any pressurized, breathable gas from theventilator to the direct nasal interface mask; b) allowing the patientto inhale and exhale air through the direct nasal interface mask toambient air while no pressurized, breathable gas is being supplied fromthe ventilator; c) detecting a condition of the patient indicative of aneed to supply pressurized, breathable gas from the ventilator to thepatient via direct nasal interface mask; and d) initiating flow of thepressurized, breathable gas from the ventilator to the patient via thedirect nasal interface mask in response to the detected condition. 20.The method of claim 19 wherein the condition of step (c) is at least oneof: i) an elapse of a set time interval; ii) a detection of a patientbreathing pattern indicative of an airway obstruction in the patient;and iii) a detection of a patient breathing pattern indicative of thepatient falling asleep.